TELEMETRY ARRANGEMENTS UTILIZING POWER DISTRIBUTING NETWORKS FOR MEASURING CONSUMPTION

摘要

1119118 Metering ELECTROMETRE SA 4 Jan 1967 [13 Jan 1966] 489/67 Headings G4D and D6Y A consumption meter which transmits data signals over the mains supply network comprises a counter 49, Fig. 1 adapted to control switch contacts when a predetermined consumption has been metered so that when the meter is monitored by, for example, a remotely generated control signal, a further switch 36 is operated at a frequency proportional to the mains supply frequency for a given time within each data transmission cycle so that bursts of a high frequency signal are superimposed on the mains by an oscillatory circuit 32. In one embodiment the counter 49 operates the switch of Fig. 2 in which contacts 54, 58 and 55, 59 are operated as a cam 57 of the counter 49 rotates. In another embodiment, Fig. 4 (not shown) the contacts are such that both pairs are not open simultaneously. The remotely generated control signal energizes a motor 48 so that in the first half of a data transmission cycle a contact 44 is closed and in the second half a contact 45 is closed so that depending on the position of the contacts associated with the counter an impulse generator 37 is selectively fed with the mains supply. During the time interval in which it receives the mains supply it operates a contact 36 closing it at a frequency of 25 c/s. for a short period, e.g. 20 milliseconds. Whilst it is closed the oscillatory circuit 32 superimposes signals of 425 or 575 cycles per second on the mains. These are filtered out at the receiver 15 and after mixing with a frequency of 500 c/s. and filtering applied to an integrator 22.